Mapbox enables you to easily design and use beautiful maps, selecting your own colors, typography, imagery, textures and line qualities from their vast and flexible toolbox. Then you can add points of interest and data from Pinterest, Foursquare, Github, spreadsheets and more.

This looks like it would be great for everything from an on-brand locator map to some serious big-data number crunching.

Hat tip to Davvi for the suggestion!